JP5598535B2 - Mobile communication system, radio relay apparatus, mobile communication apparatus, and radio communication method - Google Patents

Description

  The present invention relates to a mobile communication system, a wireless relay device, a mobile communication device, and a wireless communication method.

  Currently, mobile communication systems such as mobile phone systems and wireless MAN (Metropolitan Area Network) are widely used. In addition, active discussions are ongoing on next-generation mobile communication technologies in order to further increase the speed and capacity of wireless communication.

  In a mobile communication system, a radio relay device that relays radio communication may be provided between a base station device and a mobile communication device. By providing a wireless relay device, it is possible to cover an area (dead spot) where wireless communication is difficult due to the influence of a building, expand the range of cells managed by the base station device, and improve throughput. Some wireless relay apparatuses manage a cell independent of the cell of the base station apparatus and behave like the base station apparatus with respect to the mobile communication apparatus. For example, a method has been proposed in which a cell ID different from the cell of the base station apparatus is assigned to the cell of the radio relay apparatus so that the mobile communication apparatus does not recognize whether the access destination cell is the cell of the radio relay apparatus. (For example, refer to Section 9 of Non-Patent Document 1).

  In addition, regarding a wireless network capable of wireless communication via a plurality of nodes, a technique has been proposed in which a certain node transmits a subframe including broadcast information to another node. This subframe includes information such as identification information of the own node, a transmission output level of the own node, and route information from the core node (base station apparatus) to the own node (for example, paragraphs [0025] to [0027]).

JP 2008-109614 A

3GPP (3rd Generation Partnership Project), "Further Advancements for E-UTRA Physical Layer Aspects (Release 9)", TR 36.814 V1.5.0, 2009-11.

However, the mobile communication device has a problem that communication through the wireless relay device may not be properly controlled unless the connection destination is a base station device or a wireless relay device.
For example, when the radio relay apparatus can use less radio resources than the base station apparatus, it is preferable that the mobile communication apparatus can perform communication control considering such limitations. The same applies to the case where the timing for not performing wireless communication between the wireless relay device and the mobile communication device is set in advance in order to suppress radio wave interference. Further, when the transmission power of the radio relay apparatus is different from that of the base station apparatus, it is preferable that the mobile communication apparatus can perform quality measurement in consideration of the difference in transmission power. In addition, since the transmission delay time between the base station apparatus and the mobile communication apparatus differs depending on whether or not the wireless relay apparatus is routed, it is preferable that delay control considering the presence of the wireless relay apparatus can be performed.

  The present invention has been made in view of such points, and an object thereof is to provide a mobile communication system, a radio relay device, a mobile communication device, and a radio communication method that can appropriately control communication via the radio relay device. And

  In order to solve the above problems, a mobile communication system including a base station device, a radio relay device, and a plurality of mobile communication devices is provided. A base station device configured to generate first broadcast information used for processing by a first mobile communication device connected to the base station device and a second mobile communication device connected to the radio relay device; A first transmission unit for transmitting the first broadcast information. The wireless relay device includes a second generation unit that generates second notification information used for processing by the second mobile communication device, and a second transmission unit that transmits the second notification information. The second mobile communication device controls wireless communication performed by connecting to the wireless relay device using the receiving unit that receives the first and second broadcast information and the received first and second broadcast information. And a control unit.

  Moreover, in order to solve the said subject, the wireless relay apparatus which has a receiving part, a production | generation part, and a transmission part is provided. The receiving unit receives, from the base station device, first broadcast information used for processing by the first mobile communication device connected to the base station device and the second mobile communication device connected to the own device. The generation unit generates second notification information used for processing by the second mobile communication device. The transmission unit transmits the received first broadcast information and the generated second broadcast information.

  Moreover, in order to solve the said subject, the mobile communication apparatus which has a receiving part and a control part is provided. The receiving unit performs first broadcast information used for processing by the first mobile communication device connected to the base station device and second mobile communication device connected to the radio relay device, and processing by the second mobile communication device. Second notification information to be used is received. The control unit controls wireless communication performed by connecting to the wireless relay device, using the received first and second broadcast information.

  Moreover, in order to solve the said subject, the radio | wireless communication method is provided. The base station device transmits first broadcast information used for processing by the first mobile communication device connected to the base station device and the second mobile communication device connected to the radio relay device. The wireless relay device transmits second broadcast information used for processing by the second mobile communication device. The second mobile communication device receives the first and second notification information, and performs wireless communication with the wireless relay device based on the received first and second notification information.

According to the mobile communication system, the radio relay device, the mobile communication device, and the radio communication method, it is possible to appropriately control communication via the radio relay device.
These and other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings which illustrate preferred embodiments by way of example of the present invention.

It is a figure which shows the mobile communication system of 1st Embodiment. It is a figure which shows the mobile communication system of 2nd Embodiment. It is a figure which shows the example of a setting of a component carrier. It is a figure which shows the structural example of a radio | wireless frame. It is a figure which shows the example of allocation of an extended alerting | reporting channel. It is a figure which shows the example of a transmission / reception timing of a relay station. It is a figure which shows the example of the relay path | route between a base station and a mobile station. It is a figure which shows the example of the relay information which a relay station alert | reports. It is a block diagram which shows a base station. It is a block diagram which shows a relay station. It is a block diagram (continuation) which shows a relay station. It is a block diagram which shows a mobile station. It is a sequence diagram which shows the 1st communication example via a relay station. It is a sequence diagram which shows the 2nd communication example via a relay station. It is a block diagram which shows the base station of a 1st modification. It is a block diagram which shows the relay station of a 1st modification. It is a sequence diagram which shows the 1st modification of communication via a relay station. It is a block diagram which shows the base station of the 2nd modification. It is a sequence diagram which shows the 2nd modification of communication via a relay station. It is a block diagram which shows the mobile station of a 3rd modification. It is a sequence diagram which shows the 3rd modification of communication via a relay station.

Hereinafter, the present embodiment will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram illustrating a mobile communication system according to a first embodiment. The mobile communication system according to the first embodiment includes a base station device 1, a radio relay device 2, and mobile communication devices 3 and 4.

  The base station device 1 communicates with the mobile communication devices 3 and 4 directly or via the wireless relay device 2. The wireless relay device 2 can relay wireless communication between the base station device 1 and the mobile communication devices 3 and 4. The wireless relay device 2 may be a fixed wireless communication device or a mobile communication device. Another wireless relay device may be interposed between the base station device 1 and the wireless relay device 2. The mobile communication devices 3 and 4 connect to the base station device 1 or the wireless relay device 2 to perform wireless communication. Here, a case where the mobile communication device 3 is connected to the base station device 1 and the mobile communication device 4 is connected to the radio relay device 2 is considered.

  The base station apparatus 1 includes a first generation unit 1a and a first transmission unit 1b. The 1st production | generation part 1a produces | generates 1st alerting | reporting information. The first broadcast information is information used in common by the mobile communication device 3 connected to the base station device 1 and the mobile communication device 4 connected to the radio relay device 2. The first broadcast information includes, for example, information indicating the frequency band bandwidth used by the mobile communication system. The first transmitter 1b transmits (notifies) the first notification information generated by the first generator 1a. The first broadcast information is transmitted through a broadcast channel, for example.

  The wireless relay device 2 includes a second generation unit 2a and a second transmission unit 2b. The second generation unit 2a is information that uses the mobile communication device 4 connected to the wireless relay device 2, but does not need to use the mobile communication device 3 connected to the base station device 1. The second broadcast information includes, for example, information about radio resources that can be used by the radio relay apparatus 2, information about timing of radio communication performed by the radio relay apparatus 2, information indicating transmission power of the radio relay apparatus 2, and radio communication Including information indicating the number of relays of. The second transmitter 2b transmits (notifies) the second notification information generated by the second generator 2a. The second broadcast information is transmitted through a broadcast channel, for example.

  Here, the radio relay apparatus 2 may transfer the first broadcast information generated and transmitted by the base station apparatus 1. That is, the first broadcast information may be received from the base station apparatus 1 and the received first broadcast information may be retransmitted on the broadcast channel of the radio relay apparatus 2. At that time, the first broadcast information received from the base station apparatus 1 may be demodulated / decoded and re-encoded / remodulated for transfer. The first broadcast information and the second broadcast information may be transmitted on the same broadcast channel or different broadcast channels.

  The mobile communication device 4 includes a receiving unit 4a and a control unit 4b. The receiving unit 4a receives the first broadcast information from the base station apparatus 1 or the radio relay apparatus 2, and receives the second broadcast information from the radio relay apparatus 2. The first notification information and the second notification information may be received at the same timing or at different timings. The control unit 4b controls wireless communication performed by connecting to the wireless relay device 2 using the first and second notification information received by the reception unit 4a. The first and second notification information may be referred to when establishing a connection with the wireless relay device 2, or may be referred to in communication control after the connection is established.

  For example, the control unit 4b recognizes that the current communication partner is a wireless relay device based on information about wireless resources that can be used by the wireless relay device 2 included in the second broadcast information. Moreover, based on the information about the timing of the wireless communication performed by the wireless relay device 2, a time interval in which the wireless signal processing is stopped is set to save power. In addition, quality information and cell selection are performed for each cell using information indicating the transmission power of the wireless relay device 2. In addition, transmission delay control between the base station apparatus 1 and the mobile communication apparatus 4 is performed using information indicating the number of relays of wireless communication.

  In the mobile communication system according to the first embodiment, the base station device 1 is used for processing by the mobile communication device 3 connected to the base station device 1 and the mobile communication device 4 connected to the radio relay device 2. The first broadcast information is transmitted. Further, the wireless relay device 2 transmits second broadcast information used for processing by the mobile communication device 4. The mobile communication device 4 receives the first and second broadcast information, and performs wireless communication with the wireless relay device 2 based on the received broadcast information.

  As described above, when wireless communication is performed by connecting to the base station apparatus 1, the mobile communication apparatus 3 may refer to the first broadcast information generated by the base station apparatus 1. On the other hand, when connecting to the wireless relay device 2 and performing wireless communication, the mobile communication device 4 refers to the second notification information generated by the wireless relay device 2 in addition to the first notification information. As a result, it is possible to appropriately control communication via the wireless relay device 2.

  Such a mobile communication system can be realized, for example, as an LTE-Advanced (Long Term Evolution-Advanced, hereinafter abbreviated as LTE-A) system discussed in the 3GPP (3rd Generation Partnership Project) which is a standardization organization. . However, the above wireless communication method can of course be applied to other types of mobile communication systems.

[Second Embodiment]
FIG. 2 is a diagram illustrating the mobile communication system according to the second embodiment. The mobile communication system according to the second embodiment includes a base station 100, relay stations 200, 200a, 200b, and mobile stations 300, 400. This mobile communication system can be realized as an LTE-A system, for example.

  The base station 100 is a wireless communication device that performs wireless communication with the mobile stations 300 and 400 directly or via the relay stations 200, 200a, and 200b. The base station 100 is connected to a wired upper network (not shown), and transfers data between the upper network and the mobile stations 300 and 400. The base station 100 manages at least one cell. As will be described later, the base station 100 uses a plurality of (for example, five) frequency bands called component carriers (CC) for wireless communication. The base station may be called BS.

  The relay stations 200, 200a, and 200b are wireless communication devices that can relay wireless communication between the base station 100 and the mobile stations 300 and 400. Each of relay stations 200, 200a, and 200b manages a cell that is independent of the cell of base station 100. Different cell IDs are assigned to the cells of the base station 100 and the relay stations 200, 200a, and 200b. The relay stations 200, 200a, and 200b use a part (for example, one) of the five component carriers for wireless communication, as will be described later. The relay station may be called RS (Relay Station) or RN (Relay Node).

  The mobile stations 300 and 400 are wireless terminal devices that perform wireless communication by connecting to the base station 100 or the relay stations 200, 200a, and 200b, and are, for example, mobile phones and portable information terminal devices. Mobile stations 300 and 400 receive data from base station 100 and transmit data to base station 100. Here, the mobile station 300 connects to the base station 100 to perform wireless communication, and the mobile station 400 connects to one of the relay stations 200, 200a, and 200b (particularly, the relay station 200) to perform wireless communication. Think. The mobile station may be called MS (Mobile Station).

  FIG. 3 is a diagram illustrating a setting example of component carriers. The base station 100 can use a maximum of five component carriers (CC # 1 to CC # 5) for communication with the mobile station 300. Relay stations 200, 200a, and 200b can use a part of CC # 1 to CC # 5 (for example, CC # 3) for communication with base station 100 and mobile station 400. The reason why the relay stations 200, 200 a, and 200 b can use fewer component carriers is because it is assumed that there are fewer mobile stations than the base station 100.

  When frequency division duplex (FDD) is used for bidirectional communication, the frequency bands of CC # 1 to # 5 are secured for each of the downlink (DL: DownLink) and the uplink (UL: UpLink). Is done. Hereinafter, when simply referred to as a component carrier, it may refer to a set of a frequency band for DL and a frequency band for UL. For both DL and UL, the bandwidth of each component carrier is 20 MHz, for example, and the bandwidth of the entire mobile communication system is 100 MHz, for example. The base station 100 performs radio resource allocation (scheduling) for each of the CCs # 1 to # 5. The relay stations 200, 200a, 200b allocate radio resources used for communication with the mobile station 400.

  In the example of FIG. 3, bidirectional communication is realized by FDD, but bidirectional communication can also be realized by time division duplex (TDD). In that case, five frequency bands are provided on the frequency axis without distinguishing between DL and UL. In the above description, the bandwidth of all component carriers is set to 20 MHz, but other bandwidths (for example, 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, etc.) may be set. Moreover, it is not necessary to set the bandwidths of all component carriers to be the same.

  FIG. 4 is a diagram illustrating a structure example of a radio frame. In each of CC # 1 to CC # 5, a radio frame as shown in FIG. 4 is transmitted. Different radio frames are transmitted between the base station 100 and the relay station 200 and between the relay station 200 and the mobile station 400. Here, it is assumed that bidirectional communication is realized by FDD. The 10 ms radio frame includes 10 1 ms subframes (subframes # 0 to # 9).

  In the DL radio frame, a primary synchronization channel (P-SCH: Primary Synchronization CHannel) and a secondary synchronization channel (S-SCH: Secondary Synchronization CHannel) for transmitting a synchronization signal are set in subframes # 0 and # 5. . A physical broadcast channel (PBCH: Physical Broadcast CHannel) and an extended physical broadcast channel (E-PBCH: Extended Physical Broadcast CHannel) for transmitting broadcast information are set in subframe # 0. In subframes # 4 and # 9, a downlink physical shared channel (PDSCH) including a paging channel (PCH: Paging CHannel) for transmitting call (paging) information of the mobile station is set.

  Radio resources in the radio frame are subdivided and managed in the frequency direction and the time direction. For example, OFDMA (Orthogonal Frequency Division Multiple Access) is used for the DL frame, and SC-FDMA (Single-Carrier Frequency Division Multiple Access) or NxSC-FDMA (N Times Single-Carrier Frequency Multiple Access) is used for the UL frame. Radio resources on the frequency × time area are allocated to various channels. Radio resource allocation control is performed in units of subframes.

  For the time direction, a subframe includes two slots. A slot contains 7 or 6 symbols. An interval signal called CP (Cyclic Prefix) is inserted between symbols. There are two types of CPs with different lengths, a normal CP and an extended CP. In the case of the normal CP, 7 symbols are included in 1 slot, and in the case of the extended CP, 6 symbols are included in 1 slot. In the frequency direction, each subframe includes a plurality of subcarriers.

  FIG. 5 is a diagram illustrating an example of assignment of an extended broadcast channel. In FIG. 5, the horizontal direction is the frequency direction, and the vertical direction is the time direction. The example of FIG. 5 shows a case where a normal CP is used as the CP, that is, a case where 7 symbols are included in one slot.

  PCFICH (Physical Control Format Indicator CHannel) and PHICH (Physical Hybrid automatic repeat request Indicator CHannel) are set in the first symbol of the first half slot (slot # 0) of subframe # 0. The PCFICH is a channel for notifying the number of symbols used for a downlink physical control channel (PDCCH: Physical Downlink Control CHannel). The PHICH is a channel for returning an ACK (ACKnowledgement) response or a NACK (Negative ACKnowledgement) response to the reception of data. PHICH may be set to the third symbol.

  Also, the above PDCCH is set in the first symbol of slot # 0. The PDCCH is a channel for transmitting L1 / L2 (Layer 1 / Layer 2) control information. The PDCCH may also be set for the second and third symbols. The number of PDCCH symbols is variable between 1 and 3.

  Further, S-SCH is set for the sixth symbol of slot # 0, and P-SCH is set for the seventh symbol. P-SCH is a channel through which any one of a predetermined number (for example, three) of primary synchronization signal sequences is transmitted. S-SCH is a channel through which any one of a predetermined number (for example, 168) of secondary synchronization signal sequences is transmitted. Combinations of P-SCH sequences and S-SCH sequences (for example, 3 × 168 = 504 combinations) correspond to cell IDs.

  PBCH is set in the first to fourth symbols of the second half slot (slot # 1) of subframe # 0, and E-PBCH is set in the fifth to seventh symbols. PBCH is a broadcast channel defined in common in LTE (standard of the previous generation of LTE-A) and LTE-A. E-PBCH is a broadcast channel that is not defined in LTE. On the frequency × time region, the PBCH and the E-PBCH are adjacent in the time direction. Adjacent to each other facilitates channel detection of both. The frequency for setting the PBCH and the frequency for setting the E-PBCH may be the same or different.

  Broadcast information that is commonly referred to by the mobile station 300 connected to the base station 100 and the mobile station 400 connected to the relay station 200 (or another relay station) is transmitted by PBCH. This broadcast information includes, for example, information indicating the bandwidth of the component carrier for which PBCH is set. On the other hand, the broadcast information (relay information) related to the relay referred to by the mobile station 400 connected to the relay station 200 (or another relay station) may be transmitted on the PBCH or transmitted on the E-PBCH, as will be described later. There is a possibility that.

  In the DL radio frame, a reference signal (RS) that is a known pilot signal is transmitted using a part of radio resources other than the radio resources used for the channel. The relay stations 200, 200a, 200b and the mobile stations 300, 400 can measure received power and received quality using the reference signal.

  In addition, the setting position of E-PBCH shown in FIG. 5 is an example, and may be set to another position. For example, the following setting positions are also conceivable: (1) 4th and 5th symbols in slot # 0 (2) 4th and 5th symbols in slot # 0 and 5th to 7th symbols in slot # 1 ( 3) 7th symbol of slot # 1 (4) 4th symbol of slot # 0 (5) 6th symbol of slot # 1. Moreover, PBCH and E-PBCH may be adjacent to each other in the frequency direction on the frequency × time region.

  FIG. 6 is a diagram illustrating a transmission / reception timing example of the relay station. In order to suppress radio wave interference, relay station 200 controls DL so that reception from base station 100 and transmission to mobile station 400 are not performed simultaneously. That is, while the transmission process on the mobile station 400 side is being performed, the reception process on the base station 100 side is stopped. This is because there is a possibility that the transmission signal to the mobile station 400 will sneak into the reception circuit on the base station 100 side and the reception quality will deteriorate. Similarly, for UL, control is performed so that reception from the mobile station 400 and transmission to the base station 100 are not performed simultaneously.

  The base station 100 or the relay station 200 determines in advance the timing at which communication is not performed between the relay station 200 and the mobile station 400 (timing at which communication is performed between the base station 100 and the relay station 200). The UL timing and DL timing may be linked or may be set independently of each other. For DL, a method of setting the timing at which the relay station 200 does not transmit to the mobile station 400, for example, as the timing at which the base station 100 performs MBSFN (Multimedia Broadcast and Multicast Service Single Frequency Network) transmission is conceivable.

  MBSFN transmission is a communication mode in which a plurality of base stations transmit data having the same content at the same timing and the same frequency. A normal CP is used for a normal subframe, whereas an extended CP is used for a subframe in which MBSFN transmission is performed (MBSFN subframe). MBSFN transmission is performed in a subframe in which none of the synchronization channel (P-SCH, S-SCH), broadcast channel (PBCH, E-PBCH), and paging channel (PCH) is set. That is, MBSFN transmission is performed in any one or a plurality of subframes # 1 to # 3 and # 6 to # 8.

  Here, it is assumed that subframe # 7 is a normal subframe and subframe # 8 is an MBSFN subframe. In subframe # 7, base station 100 can transmit data to subordinate mobile station 300. Further, the relay station 200 can transmit data to the subordinate mobile station 400. However, relay station 200 does not receive data from base station 100. On the other hand, in subframe # 8, base station 100 can transmit data to relay station 200 and subordinate mobile station 300. However, the relay station 200 does not transmit data to the mobile station 400.

  Therefore, if the mobile station 400 knows that the subframe # 8 is a subframe in which the relay station 200 does not transmit data, the mobile station 400 may stop the reception process in a section in which the data of the subframe # 8 is transmitted. it can. Although the DL timing is shown in FIG. 6, the same control can be performed for the UL timing. Further, the relay stations 200a and 200b perform the same control as the relay station 200.

  The timing control includes a frequency band (or radio resource) used for communication between the base station 100 and the relay station 200, and a frequency band (or radio resource) used for communication between the relay station 200 and the mobile station 400. ) And are the same. In other words, a transmission stop period is set in order to avoid radio wave interference due to overlapping frequency bands. On the other hand, if the frequency band used between the base station 100 and the relay station 200 and the frequency band used between the relay station 200 and the mobile station 400 do not overlap, there is no need to provide a transmission stop section. Good.

  FIG. 7 is a diagram illustrating an example of a relay route between a base station and a mobile station. The base station 100 and the mobile station 400 can also communicate via a plurality of relay stations. As illustrated in FIG. 7, the relay station 200a relays wireless communication between the base station 100 and the relay station 200b. Further, when the mobile station 400 is connected to the relay station 200a, the wireless communication is relayed between the base station 100 and the mobile station 400. When the mobile station 400 connects to the relay station 200b, the relay station 200b relays wireless communication between the relay station 200a and the mobile station 400. In FIG. 7, two relay stations are connected in series, but three or more relay stations can be connected in series.

  Here, the number of hops between the base station 100 and the mobile station 400 is defined. The number of hops can be defined as the number of relay stations that pass through, for example. In this case, when the mobile station 400 connects to the relay station 200a, the number of hops is 1. When connected to the relay station 200b, the number of hops is 2 because it passes through the relay stations 200a and 200b. However, it is possible to define the number of wireless links that pass through as the number of hops. In this case, when the mobile station 400 connects to the relay station 200a, the number of hops is two. When connected to the relay station 200b, the number of hops is three.

  Further, in addition to the number of individual hops for the mobile station 400, the number of hops of the entire plurality of relay stations connected in series can be defined. The total number of hops is the number of hops when the mobile station 400 connects to a relay station farthest from the base station 100 (for example, the relay station 200b). For example, the number of relay stations is counted up from the base station 100 toward the terminal relay station, and the total number of hops determined from the terminal relay station toward the base station 100 is propagated. Can know the total number of hops.

  FIG. 8 is a diagram illustrating an example of relay information notified by the relay station. The relay station 200 broadcasts relay information as shown in FIG. 8 so that the mobile station 400 can appropriately control communication via the relay station 200. The relay information includes information on whether or not RS is used, RS timing, RS transmission power, and the number of hops. However, the relay station 200 may broadcast only some types of information among these four types. Similarly, the relay stations 200a and 200b notify the relay information.

  Information on whether or not RS is used is information (for example, a flag) indicating that the component carrier for which the relay information is broadcast is the component carrier used by the relay station 200. The mobile station 400 recognizes that the communication partner is a relay station and that the component carrier is used by the relay station by referring to the information on whether or not the RS is used.

  The RS timing information is information relating to the communication timing between the relay station 200 and the subordinate mobile stations. The mobile station 400 can intermittently stop radio signal processing (for example, reception processing of a radio signal from the relay station 200) by referring to the RS timing information. The RS timing information may include UL timing and DL timing information.

  The RS timing information may be information indicating the communication timing between the base station 100 and the relay station 200 or information indicating the communication timing between the relay station 200 and the mobile station 400. Moreover, the information which shows the timing which performs communication, or the information which shows the timing which does not perform communication may be sufficient. In any expression format, the mobile station 400 can determine the timing at which the radio signal processing can be stopped. The timing can be expressed by an arbitrary method such as a number of subframes in which data transmission is not performed (or performed), a set of subframe numbers, and the number of subframes continuous with the first subframe number.

  The RS transmission power information is information indicating the transmission power of a reference signal that is a pilot signal transmitted by the relay station 200. The mobile station 400 can calculate the propagation loss from the received power by referring to the RS transmission power information. And cell selection and transmission power control can be performed appropriately using the calculated propagation loss.

  That is, the mobile station 400 measures the received power of the reference signal, and calculates a propagation loss from the transmission power of the reference signal transmission source and the measured received power. If the transmission power is constant regardless of the transmission source and the transmission power is known, the mobile station 400 can easily calculate the propagation loss. However, it is assumed that the base station 100 and the relay station 200 have different cell radii and different reference signal transmission powers. Therefore, relay station 200 broadcasts transmission power information. The mobile station 400 can easily calculate the propagation loss by receiving the transmission power information.

  In addition, the mobile station 400 measures the reception power of the reference signal of the neighboring cell, and selects an access destination cell based on the reception power level. However, it is assumed that the transmission power of relay station 200 is smaller than the transmission power of base station 100. Therefore, in the method of simply comparing the received power levels, the mobile station 400 may select the cell of the base station 100 even if the mobile station 400 is located near the relay station 200. Therefore, when comparing the received power levels, the mobile station 400 corrects (increases) the received power level of the relay station 200 according to the calculated propagation loss. Thereby, the relay station 200 can be effectively used to improve the throughput.

  Furthermore, the mobile station 400 can control the transmission power from the mobile station 400 to the relay station 200 using the calculated propagation loss. Further, the relay station 200 can control the transmission power from the relay station 200 to the mobile station 400 by notifying the relay station 200 of the propagation loss calculated by the mobile station 400. The mobile station 400 may transmit a transmission power control (TPC) command according to the propagation loss instead of notifying the propagation loss.

  The information on the number of hops is information indicating the number of relays in the communication path passing through the relay station 200. The information on the number of hops includes information indicating the number of hops for the mobile station 400 and information indicating the number of hops of the longest communication path passing through the relay station 200. The mobile station 400 can appropriately perform transmission delay control with the base station 100 by referring to the information on the number of hops.

  That is, in the mobile communication system, the maximum transmission delay time may be set according to the required quality of service (QoS). For example, for real-time communication such as a voice call, a short maximum transmission delay time may be set. However, when the number of hops between the base station 100 and the mobile station 400 increases, the transmission delay between the two also increases. In particular, transmission delay greatly increases through a relay station that employs a relay system that demodulates / decodes, re-encodes, re-decodes and transfers the data.

  Therefore, the mobile station 400 performs transmission delay control according to the number of hops. For example, it is conceivable to set the maximum transmission delay time according to the number of hops, that is, to relax the requirement for the maximum transmission delay time as the number of hops increases. For real-time communication, it is conceivable to limit the number of hops, that is, to perform cell selection so that the number of hops becomes small. Also, subtracting the transmission delay time according to the number of hops from the maximum transmission delay time according to QoS to calculate a substantial maximum transmission delay time, and performing transmission delay control so as to satisfy the requirements of the substantial maximum transmission delay time. It is also possible to do this.

Hereinafter, a case where the base station 100 communicates with the mobile station 400 via the relay station 200 will be considered.
FIG. 9 is a block diagram showing a base station. The base station 100 includes an antenna 111, a radio reception unit 112, a demodulation / decoding unit 113, a quality information extraction unit 114, a scheduler 115, a control information generation unit 116, a broadcast information generation unit 117, a synchronization signal generation unit 118, an RS generation unit 119, A mapping unit 120, an encoding modulation unit 121, and a wireless transmission unit 122 are included.

  The antenna 111 receives a radio signal transmitted from the relay station 200 and outputs the radio signal to the radio reception unit 112. The antenna 111 wirelessly outputs the transmission signal acquired from the wireless transmission unit 122. Note that a transmitting antenna and a receiving antenna may be separately provided in the base station 100 instead of the transmitting / receiving antenna. Further, diversity transmission may be performed using a plurality of transmission / reception antennas.

  The radio reception unit 112 performs radio signal processing on the signal acquired from the antenna 111 and performs conversion (down-conversion) from a high-frequency radio signal to a low-frequency baseband signal. The wireless reception unit 112 performs, for example, a low noise amplifier (LNA), a frequency converter, a band pass filter (BPF), and A / D (Analog to Digital) conversion for wireless signal processing. Equipped with containers.

  The demodulation / decoding unit 113 demodulates and error-corrects the baseband signal acquired from the wireless reception unit 112 and outputs the obtained user data and control information. Demodulation and decoding are performed by a method corresponding to a predetermined modulation and coding scheme (MCS: Modulation and Coding Scheme) or a modulation and coding scheme instructed by the scheduler 115. The modulation scheme candidates include digital modulation schemes such as QPSK (Quadrature Phase Shift Keying) and 16QAM (Quadrature Amplitude Modulation). Encoding scheme candidates include turbo codes and low density parity check (LDPC) codes. The extracted user data is converted into a packet format and transferred to the upper network.

  The quality information extraction unit 114 extracts a radio quality measurement report, which is control information transmitted by the relay station 200. Then, the quality information extraction unit 114 outputs the extracted measurement report to the scheduler 115.

  The scheduler 115 allocates radio resources to be used for communication with the relay station 200 based on the measurement report acquired from the quality information extraction unit 114. Then, the radio resource allocation state is notified to the radio reception unit 112, the demodulation / decoding unit 113, the control information generation unit 116, the encoding modulation unit 121, and the radio transmission unit 122. Further, the scheduler 115 adaptively selects a modulation and coding scheme based on the measurement report. Then, the selected modulation and coding scheme is notified to the demodulation and decoding unit 113, the control information generating unit 116, and the coded modulation unit 121.

  Based on the notification from the scheduler 115, the control information generation unit 116 generates L1 / L2 control information to be transmitted to the relay station 200. This control information is transmitted by R-PDCCH (Relay-Physical Downlink Control CHannel) which is a DL control channel set between the base station 100 and the relay station 200. The control information includes information indicating the result of radio resource allocation and the modulation and coding scheme to be applied.

  The broadcast information generation unit 117 generates broadcast information to be transmitted on the PBCH. Specifically, the broadcast information generation unit 117 generates broadcast information that the relay station 200 and the mobile stations 300 and 400 commonly refer to for communication control. Further, the broadcast information generation unit 117 generates information used by the relay station 200 to generate relay information. For example, when the base station 100 designates the communication timing between the base station 100 and the relay station 200, information indicating the communication timing is generated.

  Synchronization signal generator 118 generates a P-SCH sequence and an S-SCH sequence corresponding to the cell ID assigned to the cell of base station 100. The RS generation unit 119 generates a reference signal that is a known signal.

  The mapping unit 120 receives the user data addressed to the mobile station 400 received from the upper network, the control information / control signal generated by the control information generation unit 116, the broadcast information generation unit 117, the synchronization signal generation unit 118, and the RS generation unit 119. Are mapped to DL radio frames. Then, the mapped data is sequentially output to the encoding modulation unit 121. User data addressed to the mobile station 400 is transmitted on a R-PDSCH (Relay-Physical Downlink Shared CHannel) which is a DL data channel set between the base station 100 and the relay station 200.

  The code modulation unit 121 performs error correction coding and modulation on the data acquired from the mapping unit 120, generates a baseband signal as a transmission signal, and outputs the baseband signal to the radio transmission unit 122. For the encoding and modulation, a predetermined modulation encoding method or a modulation encoding method instructed by the scheduler 115 is used.

  The radio transmission unit 122 performs radio signal processing on the transmission signal acquired from the encoding modulation unit 121 and performs conversion (up-conversion) from a low-frequency baseband signal to a high-frequency radio signal. The wireless transmission unit 122 includes, for example, a D / A (Digital to Analog) converter, a frequency converter, a band pass filter, a power amplifier, and the like for wireless signal processing.

  FIG. 10 is a block diagram illustrating a relay station. The relay station 200 includes an antenna 211, a radio reception unit 212, a demodulation decoding unit 213, a control information extraction unit 214, a broadcast information extraction unit 215, a synchronization signal extraction unit 216, a synchronization control unit 217, a relay control unit 218, and an encoding modulation unit. 219 and a wireless transmission unit 220. FIG. 10 shows units related to communication on the base station 100 side.

  The antenna 211 receives a radio signal transmitted from the base station 100 and outputs it to the radio reception unit 212. In addition, the transmission signal acquired from the wireless transmission unit 220 is wirelessly output. The radio reception unit 212 performs radio signal processing on the signal acquired from the antenna 211 and down-converts the radio signal into a baseband signal. The demodulation / decoding unit 213 demodulates and error-corrects the baseband signal acquired from the wireless reception unit 212 and outputs the obtained user data and control information.

  The control information extraction unit 214 extracts L1 / L2 control information transmitted by the base station 100 using the R-PDCCH. As described above, this control information includes radio resource allocation results and information indicating the modulation and coding scheme to be applied. Then, the control information extraction unit 214 outputs the extracted control information to the relay control unit 218.

  The broadcast information extraction unit 215 extracts the broadcast information transmitted by the base station 100 using the PBCH. As described above, the broadcast information that is extracted includes information that the relay station 200 and the mobile stations 300 and 400 commonly refer to for communication control, and information that the relay station 200 uses to generate relay information. . The broadcast information extraction unit 215 outputs the extracted broadcast information to the relay control unit 218.

  The synchronization signal extraction unit 216 extracts synchronization signals (primary synchronization signal and secondary synchronization signal) transmitted by the base station 100 using P-SCH and S-SCH. Then, the synchronization signal extraction unit 216 outputs the synchronization signal to the synchronization control unit 217.

  Based on the synchronization signal extracted by the synchronization signal extraction unit 216, the synchronization control unit 217 detects the timing of a radio frame having a 10 ms cycle and the timing of a slot having a 0.5 ms cycle. Further, the P-SCH sequence and the S-SCH sequence used by the base station 100 are specified, and the cell ID is specified from the combination of both. Then, the detected timing and the specified cell ID are notified to the relay control unit 218.

  Based on the control information extracted by the control information extraction unit 214, the broadcast information extracted by the broadcast information extraction unit 215, and the timing detected by the synchronization control unit 217, the relay control unit 218 Operations of the unit 213, the encoding / modulation unit 219, and the wireless transmission unit 220 are controlled. Also, the relay control unit 218 determines what type of broadcast information is to be transmitted to the subordinate mobile station based on the broadcast information extracted by the broadcast information extraction unit 215.

  The code modulation unit 219 performs error correction coding and modulation on the data acquired from the mobile station 400 side, generates a baseband signal as a transmission signal, and outputs the baseband signal to the radio transmission unit 220. The radio transmission unit 220 performs radio signal processing on the transmission signal acquired from the encoding modulation unit 219 and up-converts the baseband signal to a radio signal.

  FIG. 11 is a block diagram (continued) showing the relay station. The relay station 200 further includes an antenna 221, a radio reception unit 222, a demodulation decoding unit 223, a quality information extraction unit 224, a scheduler 225, a control information generation unit 226, an extended notification information generation unit 227, a notification information generation unit 228, a synchronization signal. A generation unit 229, an RS generation unit 230, a mapping unit 231, an encoding modulation unit 232, and a wireless transmission unit 233 are included. FIG. 11 shows units related to communication on the mobile station 400 side.

  The antenna 221 receives the radio signal transmitted by the mobile station 400 and outputs it to the radio reception unit 222. The transmission signal acquired from the wireless transmission unit 233 is wirelessly output. The radio reception unit 222 performs radio signal processing on the signal acquired from the antenna 221 and down-converts the radio signal into a baseband signal. The demodulation / decoding unit 223 demodulates and error-corrects the baseband signal acquired from the wireless reception unit 222 and outputs the obtained user data and control information.

  The quality information extraction unit 224 extracts a radio quality measurement report, which is control information transmitted by the mobile station 400. Then, the quality information extraction unit 224 outputs the extracted measurement report to the scheduler 225.

  Based on the measurement report acquired from the quality information extraction unit 224, the scheduler 225 allocates radio resources used for communication with the mobile station 400 and adaptively selects a modulation and coding scheme. Then, it notifies the relay control unit 218 and the control information generation unit 226 of the radio resource allocation status and the selected modulation and coding scheme. The relay control unit 218 notifies the radio reception unit 222, the demodulation / decoding unit 223, the encoding / modulation unit 232, and the radio transmission unit 233 of the radio resource allocation status and the modulation and coding scheme.

  The control information generation unit 226 generates L1 / L2 control information to be transmitted to the mobile station 400 based on the notification from the scheduler 225. This control information is transmitted on the PDCCH set between the relay station 200 and the mobile station 400. The control information includes information indicating the result of radio resource allocation and the modulation and coding scheme to be applied.

  Based on an instruction from the relay control unit 218, the extended notification information generation unit 227 generates extended notification information to be transmitted to the mobile stations being served by the E-PBCH. The extended notification information includes the relay information described above. The relay information is generated with reference to information (information used to generate relay information) transmitted by the base station 100 using the PBCH. For example, it is conceivable that the RS timing information in the relay information is the content indicating the communication timing designated by the base station 100, and the other information is the content determined by the relay station 200.

  Based on an instruction from the relay control unit 218, the broadcast information generation unit 228 generates broadcast information to be transmitted to the subordinate mobile station using the PBCH. Specifically, the broadcast information generation unit 228 generates broadcast information that the mobile stations 300 and 400 commonly refer to for communication control. This broadcast information has the same content as that transmitted by the base station 100 using the PBCH.

  The synchronization signal generation unit 229 generates a P-SCH sequence and an S-SCH sequence corresponding to the cell ID assigned to the cell of the relay station 200. The RS generation unit 230 generates a reference signal that is a known signal.

  The mapping unit 231 is generated by the user data addressed to the mobile station 400 received from the base station 100, the control information generation unit 226, the extended notification information generation unit 227, the notification information generation unit 228, the synchronization signal generation unit 229, and the RS generation unit 230. The control information / control signal thus mapped is mapped to the DL radio frame. Then, the mapped data is sequentially output to the encoding modulation unit 232. User data addressed to the mobile station 400 is transmitted on the PDSCH set between the relay station 200 and the mobile station 400.

  The code modulation unit 232 performs error correction coding and modulation on the data acquired from the mapping unit 231, generates a baseband signal as a transmission signal, and outputs the baseband signal to the radio transmission unit 233. The radio transmission unit 233 performs radio signal processing on the transmission signal acquired from the encoding modulation unit 232 and up-converts the baseband signal to a radio signal.

  FIG. 12 is a block diagram showing a mobile station. The mobile station 400 includes an antenna 411, a radio reception unit 412, a demodulation decoding unit 413, a control information extraction unit 414, a broadcast information extraction unit 415, an extended broadcast information extraction unit 416, a delay control unit 417, a terminal control unit 418, and a synchronization signal extraction. A unit 419, a synchronization control unit 420, an RS extraction unit 421, a quality measurement unit 422, a quality information generation unit 423, an encoding modulation unit 424, and a wireless transmission unit 425. The mobile station 300 can also be realized by the same block configuration as the mobile station 400.

  The antenna 411 receives the radio signal transmitted from the relay station 200 and outputs it to the radio reception unit 412. Further, the transmission signal acquired from the wireless transmission unit 425 is wirelessly output. The radio reception unit 412 performs radio signal processing on the signal acquired from the antenna 411 and down-converts the radio signal into a baseband signal. The demodulation / decoding unit 413 demodulates and error-corrects the baseband signal acquired from the wireless reception unit 412 and outputs the obtained user data and control information.

  The control information extraction unit 414 extracts L1 / L2 control information transmitted by the relay station 200 using the PDCCH. As described above, this control information includes radio resource allocation results and information indicating the modulation and coding scheme to be applied. Then, the control information extraction unit 414 outputs the extracted control information to the terminal control unit 418.

  Broadcast information extraction section 415 extracts broadcast information transmitted by relay station 200 using PBCH. The broadcast information includes information indicating the frequency bandwidth of the component carrier to which the broadcast information is transmitted. The broadcast information extraction unit 415 outputs the extracted broadcast information to the terminal control unit 418.

  Extended broadcast information extraction section 416 extracts extended broadcast information transmitted by relay station 200 using E-PBCH. As described above, the extended broadcast information includes relay information indicating whether RS is used, RS timing, RS transmission power, the number of hops, and the like. The extended notification information extraction unit 416 notifies the terminal control unit 418 of whether or not RS is used. In addition, the RS timing is notified to the terminal control unit 418, the synchronization control unit 420, the quality measurement unit 422, and the quality information generation unit 423. The RS transmission power is notified to at least one of the quality measurement unit 422 and the quality information generation unit 423. The delay control unit 417 is notified of the number of hops.

  The delay control unit 417 controls the transmission delay with the base station 100 based on the number of hops notified from the extended broadcast information extraction unit 416. For example, the maximum transmission delay time is set according to the number of hops, and it is determined whether or not the current communication path has a requirement for the maximum transmission delay time. Then, the terminal control unit 418 is notified of the result of the transmission delay control.

  The terminal control unit 418 receives the control information extracted by the control information extraction unit 414, the notification information extracted by the notification information extraction unit 415, the notification from the extended notification information extraction unit 416, and the notification from the delay control unit 417. get. Then, based on the acquired information, the operations of the wireless reception unit 412, the demodulation decoding unit 413, the encoding modulation unit 424, and the wireless transmission unit 425 are controlled. In particular, the reception processing of the radio reception unit 412 and the demodulation decoding unit 413 is intermittently stopped based on the RS timing included in the extended broadcast information. As a method for stopping the reception processing, for example, there are methods such as stopping power supply, stopping clock supply, and lowering the clock frequency.

  Synchronization signal extraction section 419 extracts synchronization signals (primary synchronization signal and secondary synchronization signal) transmitted by relay station 200 using P-SCH and S-SCH. Then, the synchronization signal extraction unit 419 outputs the synchronization signal to the synchronization control unit 420.

  Based on the synchronization signal extracted by the synchronization signal extraction unit 419, the synchronization control unit 420 detects the timing of a radio frame having a 10 ms cycle and the timing of a slot having a 0.5 ms cycle. The detected timing is notified to the RS extraction unit 421 and fed back to the synchronization signal extraction unit 419. Also, synchronization control section 420 identifies the P-SCH sequence and S-SCH sequence used by relay station 200, and identifies the cell ID from the combination of both.

  The RS extraction unit 421 extracts the reference signal transmitted by the relay station 200 based on the radio frame and slot timing detected by the synchronization control unit 420. Then, the extracted reference signal is output to quality measuring section 422.

  The quality measurement unit 422 measures the reception quality of the component carrier used by the relay station 200 using the reference signal extracted by the RS extraction unit 421. The measurement result is notified to the quality information generation unit 423 and fed back to the RS extraction unit 421. The quality information generation unit 423 generates control information (measurement report) indicating the reception quality measured by the quality measurement unit 422. As the measurement report, for example, CQI (Channel Quality Indication) in which the reception quality is represented by a discrete value can be used. Quality measuring section 422 or quality information generating section 423 corrects the value indicating the measured reception quality according to the transmission power of relay station 200.

  The code modulation unit 424 performs error correction coding and modulation on user data and control information to be transmitted to the relay station 200, generates a baseband signal as a transmission signal, and outputs the baseband signal to the radio transmission unit 425. The radio transmission unit 425 performs radio signal processing on the transmission signal acquired from the coding modulation unit 424 and up-converts the baseband signal to a radio signal.

FIG. 13 is a sequence diagram illustrating a first communication example via the relay station. The process illustrated in FIG. 13 will be described along with step numbers.
(Step S11) The base station 100 transmits a synchronization signal (a primary synchronization signal and a secondary synchronization signal) according to the cell ID of the cell managed by the base station 100 using the P-SCH and the S-SCH. The relay station 200 receives the synchronization signal from the base station 100.

(Step S12) The relay station 200 detects the timing of the radio frame and the slot based on the received synchronization signal, and synchronizes with the base station 100.
(Step S13) The base station 100 transmits a reference signal which is a known signal. The relay station 200 receives the reference signal from the base station 100.

  (Step S14) The relay station 200 measures received power based on the received reference signal. Similarly, when there are other base stations and relay stations, the received power is measured for these connection destination candidates. Then, an access destination cell (that is, a connection destination base station or another relay station) is selected. Here, a case where the base station 100 is selected is considered.

  (Step S15) The base station 100 transmits broadcast information using the PBCH. This broadcast information includes information indicating the bandwidth of the component carrier. Moreover, the information (for example, information of RS timing) used for the production | generation of the relay information which the relay station 200 alert | reports is also contained. The relay station 200 receives broadcast information from the base station 100.

  (Step S16) The relay station 200 refers to the received broadcast information and performs a procedure for line connection with the base station 100. Note that the processes in steps S11 to S16 described above can be omitted when a line is already established between the base station 100 and the relay station 200.

  (Step S <b> 17) The relay station 200 transmits a synchronization signal (primary synchronization signal and secondary synchronization signal) corresponding to the cell ID of the cell managed by the relay station 200 using P-SCH and S-SCH. The mobile station 400 receives the synchronization signal from the relay station 200.

(Step S18) The mobile station 400 detects the timing of the radio frame and the slot based on the received synchronization signal, and synchronizes with the relay station 200.
(Step S19) The relay station 200 transmits a reference signal which is a known signal. The mobile station 400 receives the reference signal from the relay station 200.

  (Step S20) The mobile station 400 measures received power based on the received reference signal. Similarly, the received power is measured for the base station 100 and other relay stations. Then, an access destination cell (that is, a connection destination base station or relay station) is selected. Here, the case where the relay station 200 is selected is considered.

  (Step S21) Relay station 200 generates its own broadcast information using the broadcast information received in step S15, and transmits it using PBCH. As with the base station 100, the broadcast information includes information indicating the bandwidth of the component carrier. Moreover, relay information is produced | generated using the received alerting | reporting information, and it transmits as extended alerting | reporting information by E-PBCH. As described above, the relay information may include information indicating whether or not RS is used, RS timing, RS transmission power, and the number of hops. The mobile station 400 receives broadcast information and extended broadcast information from the relay station 200.

  Note that, after the base station 100 and the relay station 200 establish a line, the base station 100 may update information (for example, RS timing information) used to generate relay information. The base station 100 may notify the information every time it is updated, or may notify periodically. The relay station 200 generates relay information based on the latest broadcast information received from the base station 100.

(Step S <b> 22) The mobile station 400 refers to the received broadcast information and performs a line connection procedure with the relay station 200.
(Step S <b> 23) The mobile station 400 performs transmission delay control between the base station 100 and the mobile station 400 based on the hop count information included in the extended broadcast information.

(Step S24) The mobile station 400 performs control to intermittently stop the reception process based on the RS timing information included in the extended broadcast information.
(Step S25) The mobile station 400 refers to the RS transmission power information included in the extended broadcast information, and measures the radio quality for the relay station 200. Note that the processes of steps S23 to S25 can be executed in any order.

(Step S26) The mobile station 400 feeds back the quality information indicating the radio quality measured in step S25 to the relay station 200.
(Step S <b> 27) When the base station 100 receives user data addressed to the mobile station 400 from the upper network, the base station 100 transmits the user data to the relay station 200 using the R-PDSCH. Moreover, the control information accompanying transmission of user data is transmitted to the relay station 200 by R-PDCCH. The relay station 200 receives user data addressed to the mobile station 400 from the base station 100.

  (Step S28) The relay station 200 transfers the received user data to the mobile station 400 by PDSCH. At that time, user data is demodulated / decoded and re-encoded / remodulated. In addition, control information accompanying transmission of user data is transmitted to mobile station 400 using PDCCH.

Here, in the sequence example of FIG. 13, the mobile station 400 receives both broadcast information and extended broadcast information from the relay station 200, but may receive broadcast information from the base station 100.
FIG. 14 is a sequence diagram illustrating a second communication example via the relay station. In the sequence example of FIG. 14, steps S21a and S21b are executed instead of step S21 of FIG.

  (Step S21a) The base station 100 transmits broadcast information using PBCH. This broadcast information includes information indicating the bandwidth of the component carrier. The mobile station 400 receives broadcast information from the base station 100.

  (Step S <b> 21 b) The relay station 200 generates relay information using the broadcast information received in Step S <b> 15 and transmits it as extended broadcast information using the E-PBCH. The mobile station 400 receives the extended broadcast information from the relay station 200.

  Thus, when the mobile station 400 can receive a radio signal from the base station 100, the mobile station 400 may receive the broadcast information transmitted by the base station 100 and use it for communication control. Note that the broadcast information from the base station 100 and the extended broadcast information from the relay station 200 may be received in the same radio frame or in different radio frames.

Next, modified examples of a method for notifying information used for generating relay information from base station 100 to relay station 200 and a method for reporting relay information of relay station 200 will be described.
FIG. 15 is a block diagram illustrating a base station according to the first modification. The base station 100a according to the first modification transmits information used for generation of relay information by E-PBCH instead of PBCH. The base station 100a includes a notification information generation unit 117a instead of the notification information generation unit 117 of the base station 100. In addition, an extended notification information generation unit 123 is included.

  The broadcast information generation unit 117a generates broadcast information transmitted on the PBCH. This broadcast information includes information that the mobile stations 300 and 400 and the relay station 200c described below commonly refer to for communication control. However, information used for generating relay information (for example, information indicating communication timing between the base station 100a and the relay station 200c) is not included. The extended broadcast information generation unit 123 generates extended broadcast information transmitted on the E-PBCH. The extended notification information includes information used for generating relay information.

  FIG. 16 is a block diagram showing a relay station of the first modification. The relay station 200c according to the first modification receives information used to generate relay information from the base station 100a via the E-PBCH. Relay station 200c has broadcast information extraction section 215c instead of broadcast information extraction section 215 of relay station 200. In addition, an extended notification information extraction unit 234 is provided.

  The broadcast information extraction unit 215c extracts the broadcast information transmitted by the base station 100a using the PBCH. As described above, the broadcast information includes information that the relay station 200c and the mobile stations 300 and 400 commonly refer to for communication control. However, information used for generating relay information is not included. The extended notification information extraction unit 234 extracts the extended notification information transmitted from the base station 100c by E-BPCH. As described above, the extended broadcast information includes information used by the relay station 200c to generate relay information.

FIG. 17 is a sequence diagram illustrating a first modification of communication via a relay station. In the sequence example of FIG. 17, step S15a is executed instead of step S15 of FIG.
(Step S15a) Base station 100a transmits broadcast information using PBCH. This broadcast information includes information indicating the bandwidth of the component carrier. Moreover, the base station 100a transmits the extended broadcast information using E-PBCH. This extended broadcast information includes information (for example, RS timing information) used to generate relay information broadcast by the relay station 200c. The relay station 200c receives broadcast information and extended broadcast information from the base station 100a.

  FIG. 18 is a block diagram illustrating a base station according to the second modification. The base station 100b according to the second modification transmits information used for generation of relay information by R-PDCCH instead of PBCH. The base station 100b includes a notification information generation unit 117b instead of the notification information generation unit 117 of the base station 100. In addition, a relay control information generation unit 124 is included.

  The broadcast information generation unit 117b generates broadcast information transmitted on the PBCH. This broadcast information includes information that the mobile stations 300 and 400 and the relay station 200d described below commonly refer to for communication control. However, information used for generating relay information (for example, information indicating communication timing between the base station 100a and the relay station 200d) is not included. The relay control information generation unit 124 generates control information transmitted to the relay station 200d using the R-PDCCH. This control information includes information used for generating relay information.

  The relay station 200d can be realized by the same block configuration as the relay station 200 shown in FIGS. In this case, the control information extraction unit 214 extracts information used for generation of relay information, which is transmitted from the base station 100b to the relay station 200d using the R-PDCCH.

  FIG. 19 is a sequence diagram illustrating a second modification of communication via a relay station. In the sequence example of FIG. 19, step S15b is executed instead of step S15 of FIG. Further, Step S16a is executed between Step S16 and Step S17.

  (Step S15b) The base station 100b transmits broadcast information using the PBCH. This broadcast information includes information indicating the bandwidth of the component carrier. However, information (for example, RS timing information) used for generation of relay information is not included. The relay station 200d receives broadcast information from the base station 100b.

  (Step S16a) The base station 100b transmits the control information for relay control by R-PDCCH after the procedure of line connection. This control information includes information used for generating relay information. The relay station 200d receives control information from the base station 100b.

  As described above, the base station 100b may update information (for example, RS timing information) used to generate relay information. Each time the base station 100b is updated, the control information may be transmitted to the relay station 200d using the R-PDCCH, or may be periodically transmitted. The relay station 200d generates relay information based on the latest control information received from the base station 100b.

  FIG. 20 is a block diagram showing a mobile station according to the third modification. The mobile station 400a according to the third modified example receives the relay information by PBCH from the relay station 200e according to the third modified example described below. The mobile station 400a includes a broadcast information extraction unit 415a instead of the broadcast information extraction unit 415 of the mobile station 400. On the other hand, the mobile station 400a may not have the extended broadcast information extraction unit 416.

  The broadcast information extraction unit 415a extracts the broadcast information transmitted by the relay station 200e using the PBCH. This broadcast information includes information indicating the frequency bandwidth of the component carrier to which the broadcast information is transmitted. The broadcast information includes relay information indicating whether or not RS is used, RS timing, RS transmission power, the number of hops, and the like. The broadcast information extraction unit 415a distributes the content of the extracted broadcast information to the delay control unit 417, the terminal control unit 418, the synchronization control unit 420, the quality measurement unit 422, and the quality information generation unit 423 according to the type of information. Notice.

  Relay station 200e can be realized by the same block configuration as relay station 200 shown in FIGS. In that case, the notification information generation unit 228 generates notification information including relay information based on an instruction from the relay control unit 218.

FIG. 21 is a sequence diagram illustrating a third modification of communication via a relay station. In the sequence example of FIG. 21, step S21a is executed instead of step S21 of FIG.
(Step S21a) The relay station 200e generates its own broadcast information using the broadcast information received in Step S15, and transmits it using PBCH. This broadcast information includes information indicating the bandwidth of the component carrier. Moreover, the relay information which shows the presence or absence of RS use, RS timing, RS transmission power, the number of hops, etc. is contained. That is, relay station 200e transmits both relay information and other broadcast information using PBCH. The mobile station 400a receives broadcast information from the relay station 200e.

  In the above description of the second embodiment, the base station 100 determines the RS timing and notifies the relay station 200, but the relay station 200 determines and notifies the base station 100. May be. In this case, the relay station 200 may use a method of transmitting RS timing information to the base station 100 using a UL control channel set between the base station 100 and the relay station 200.

  In the above description of the second embodiment, the cell of relay station 200 is assigned a cell ID that is different from the cell of base station 100 and is distinguished from cell of base station 100 from mobile station 400. It was supposed to be. However, the relay information notification method described above can also be applied to a system in which the cell of relay station 200 is recognized as a part of the cell of base station 100 from mobile station 400.

  According to such a mobile communication system according to the second embodiment, the mobile station 400 can appropriately control the wireless communication via the relay station 200 (or the relay stations 200a and 200b). That is, the mobile station 400 can receive the broadcasted relay information and know that the access destination cell is the cell of the relay station and the component carrier used by the relay station. Further, it is possible to know the transmission timing of the connected relay station, and to stop radio signal processing intermittently. Thereby, power consumption is suppressed.

  For example, it is assumed that wireless communication between the base station 100 and the relay station 200 is performed in 4 subframes among 10 subframes included in the wireless frame. If the mobile station 400 does not know the communication timing, the mobile station 400 receives a radio signal from the relay station 200 in all sections (10 subframes), and determines the presence / absence of data addressed to itself. On the other hand, if the communication timing is known, mobile station 400 can determine in advance that it is not necessary to receive a radio signal from relay station 200 in four subframes. Therefore, in this case, the load of reception processing can be reduced to 6/10, and the power consumption of the mobile station 400 is suppressed.

  Further, the mobile station 400 can know the transmission power of the relay stations 200, 200a, and 200b, and can calculate the propagation loss from the transmission power and the reception power. Thereby, even when the transmission power of the relay stations 200, 200a, and 200b is different from that of the base station 100, cell selection and transmission power control can be appropriately executed. Further, the number of hops between the base station 100 and the mobile station 400 can be known, and transmission delay control according to the number of hops can be executed.

  The above merely illustrates the principle of the present invention. In addition, many modifications and changes can be made by those skilled in the art, and the present invention is not limited to the exact configuration and application shown and described above, and all corresponding modifications and equivalents may be And the equivalents thereof are considered to be within the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Base station apparatus 1a 1st production | generation part 1b 1st transmission part 2 Radio relay apparatus 2a 2nd production | generation part 2b 2nd transmission part 3, 4 Mobile communication apparatus 4a Reception part 4b Control part

Claims (10)

A mobile communication system including a base station device, a radio relay device, and a plurality of mobile communication devices,
The base station apparatus generates first broadcast information used for processing by a first mobile communication apparatus connected to the base station apparatus and a second mobile communication apparatus connected to the radio relay apparatus. And a first transmission unit for transmitting the first broadcast information,
The wireless relay device includes: a second generation unit that generates second notification information used for processing by the second mobile communication device; and a second transmission unit that transmits the second notification information. Have
The second mobile communication device is connected to the wireless relay device using the receiving unit that receives the first and second broadcast information, and the received first and second broadcast information. A control unit that controls wireless communication to be performed,
A mobile communication system.   The second transmission unit transfers the first broadcast information transmitted by the base station apparatus through a first broadcast channel, and transmits the second broadcast information through a second broadcast channel. The mobile communication system according to claim 1.   The movement according to claim 2, wherein at least one of a frequency and a time is adjacent to a radio resource in which the first broadcast channel is set and a radio resource in which the second broadcast channel is set. Communications system.   The mobile communication system according to claim 1, wherein the second broadcast information includes information on radio resources that can be used by the radio relay device among radio resources used by the mobile communication system.   The mobile communication system according to claim 1, wherein the second broadcast information includes information about a timing of wireless communication performed by the wireless relay device.   The mobile communication system according to claim 1, wherein the second broadcast information includes information about transmission power of the wireless relay device.   The mobile communication system according to claim 1, wherein the second broadcast information includes information on the number of relays between the base station apparatus and the second mobile communication apparatus.   A receiving unit for receiving, from a base station device, first broadcast information used for processing by a first mobile communication device connected to the base station device and a second mobile communication device connected to the own device;
  A generator for generating second broadcast information used for processing by the second mobile communication device;
  A transmission unit for transmitting the received first broadcast information and the generated second broadcast information;
  A wireless relay device comprising:   First broadcast information used for processing by the first mobile communication device connected to the base station device and second mobile communication device connected to the radio relay device, and first information used for processing by the second mobile communication device. 2 broadcast information, a receiving unit for receiving,
  A control unit that controls wireless communication performed by connecting to the wireless relay device using the received first and second notification information;
  A mobile communication device that operates as the second mobile communication device.   The base station device transmits first broadcast information used for processing by the first mobile communication device connected to the base station device and the second mobile communication device connected to the radio relay device;
  The wireless relay device transmits second broadcast information used for processing by the second mobile communication device;
  The second mobile communication device receives the first and second notification information, and performs wireless communication with the wireless relay device based on the received first and second notification information;
  A wireless communication method.

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